Automatic stoker



July 11, 1933. G. A. KOHOUT AUTOMATIC STOKER G. A. KOHOUT AUTOMATI C STOKER Filed April 24, 1929 3 Sheets-Sheet 5 &

July 11, 1933.

Patented July 11, 1933 GEORGE A. KOHOUT, OF CHICAGO, ILLINOIS AUTOMATIC STOKEE Application filed April 24, 1929. Serial No. 357,703.

M invention relates to automatic furnace regulation, and more particularly to means whereby the feeding of fuel to t e furnace, the introduction of proper air for combustion, and the regulation of the damper controlling the outlet of the gaseous products of combustion, are all controlled in such manner as to cause the most efiicient burnin g of the fuel introduced into the furnace.

One of the principal objects of the invention is to provide in a device of this character means whereby the fuel feeding operation may be automatically stopped when a certain temperature or steam pressure is reached in the furnace or in the boilers heated thereb and thereafter to automatically position t e damper to its most efficient position and at the same time to regulate the introduction of air for combustion. One of theprincipal features of advantage in this system lies in the fact that the damper control is operated from and therefore. necessarily regulated with the stoker motor.

It is also a purpose of this 5 invention to provide in a device of this character novel means for operating the damper to change its position at a predetermined time after feeding the fuel is cut off.

It is also a purpose of this invention to provide in a furnace having a stoker grate, meansfor operatin the stoker grate and fuel feedin mechanism from a common m0- tor and drive shaft, and to provide in connection with said drive shaft suitable mechanism for opening and closing the damper of the furnace at the proper time.

In carrying out the objects of this invention, I prefer to employ a fuel feeding mechanism similar to that shown in my prior application Serial No. 302,394, filed Au st 27, 1928; and a stoker mechanism similar to that shown in my application Serial No. 302,395, filed August 27, 1928; in combination with certain other features of automatic control for these devices in combination with the furnace damper so that all of the operations of the furnace are properly coordinated to give efiicient automatic operation of the furnace.

with.

All of the moving parts of the furnace are driven from a common motor which is preferabl controlled by a suitable switch that may be element reflectin the furnace and t the thermal condition of e boilers associated there- It is obvious, of course, that any suitable thermostat or steam pressure responsive device may be used to control the switch. In the form shown, I prefer to use a switch that is controlled by steam pressure in the boilers heated by the furnace.

Other ob'ects and advantages of the invention will appear as the description proceeds in connection with the accompanying drawin s. However, I wish it to be understood t at the drawings are merely illustrative'of the preferred form of mechanism for carrying out the invention, and that I intend to avail myself of all modifications that fall within the scope of the claims.

In the drawings:

Fig. 1 is a front view of a portion of a furnace illustrating part of the. automatic control mechanism in combination with the fuel feeding and stoker operating means" Fig. 2 is a vertical section on line 22 of Fig. 1 through the front portion'of thefurnace showing more in detail the application of the damper control to the furnace;

Fig. 3 is adetailed sectional view showing the damper control mechanism in a differen position from that shown in Fig. 2;

Fig. 4 is a diagrammatic view of the damper in the outlet of the furnace and the means for operatively connecting it to the control mechanism;

, Fig. 5 is a fragmentary perspective view of the side of the furnace front opposite to that shown in Fig. 1, and illustrates the connectior; of the fuel feeding bars to the main drive sha t;

Figs. 6 and 7 are details of a art of the merchanism used'in controlling t e dam r, Fig. 6 being a section on the line 6-6 of ig. 7, and Fig. 7 being a section substantially on the line 7-4 of Fig. 6; and

Fig. 8 is a simple wiring diagram showing the connections of the motor-to a source of,

current.

responsive to anypressure or heat Fig. 9 is a plan detail partly in section of the fuel feeding pushers.

Referring now in detail to the drawings, I show at 10 a drive motor which is adapted through the interposition of suitable connecting mechanism and reduction gearing, to rotate a crank ll'that is connected by the link 12 to a main drive shaft 13 so as to impart a rocking motion to this shaft through an angle of about-fifty (50) degrees. This motor may be driven from a suitable source of current such as indicated in Fig. 8 by the power lines 14 and 15, one side of the motor being connected through a manually controlled switch 16, a pressure controlled switch 17, and a limit switch 18, and the other side of the motor being connected directly to the source of current. suitable overload protective device for the motor may be used.

The position of the switch=16, as shown in Fig. 8, is such as to connect the switches 17 and 18 in parallel so that both of themmust open before the motor will stop although the closing of either of them will start the motor. Now, by moving the switch 16 so as to connct with the terminal 19, the motor may be operated independently of either of the switches 17 and 18 if desired. Similarly, if the switch 16 is moved into position to contact with the dead terminal 20, current to the motor is cut off entirely.- Switch 17 is preferably operated by a suitable device responsive to the pressure in the steam boilers heated by the furnace. That is, a suitable device is provided for closing switch 17 when the steam pressure drops below a certain predetermined value and for opening the switch 17 when the steam pressure reaches a certain predetermined high limit. This however is common and switch 17 may be manual as shown.

Switch 18 is preferablyconnected so as to be opened each time the shaft 13 rocks into a certain position at one end of its stroke. This switch 18 is shown as mounted directly below the shaft 13 on the frame member 21 of the furnace, and a suitable arm 22 on shaft 13 contacts with the button 23 of the switch 18 to open the switch each time the shaft is in the position shown in Fig. 2. The purpose of this limit switch 18 is as more fully brought out in my application Serial No. 302,395, to bring the stoker grates into level position at the time the motor stops. Thus the opening ofswitch 17, due to the steam pressure rising to the predetermined value, does not immediately stop the motor which can also receive current through switch 18 until the shaft is rotated ing the arm 22 in position to open the s The mechanisn for operating stoker grates 24 is the same as-that shown my pl1cat1on302,395, and consists of a it link 25 and lever arm 26 togethe w.

It is obvious, however, that any.

tain mechanism indicated generally by the numeral 27 for periodically imparting to the stokers a rocking motion.

Shaft 13 also operates, through the medium of the crank 28, link 29, and bell crank 30, a pitman 31. This pitman operates, through the medium of the bars 32 and 33, a plurality of cranks such as indicated at 34 to alternately advance and retract the pusher bars 35. Rocker arm 34 as indicated in Fig. 9 is pivoted on a pin 34' and has laterally extending arms 125 and 126 to which links 127-and 128 are secured by a pin and slot connection, the other ends of links 127 and 128 being pivoted as shown in Figs. 2 and 9 to the pushers 35 at 129. Thus when bars 32, 33 are reciprocated by crank 30 and pitman 31, rocker arm 34 will rock and each retract one of its pushers while advancing the other. These burning in suspension from the coarse material which must be burned on the grates, a suitable blast of air mixed with steam is directed through the openings 38 across the ath of the coal as it is falling. The air is controlled by suitable dampers 39 and the steam jets through pipes 40 are controlled by suitable valves indicated generally at 41. The dampers 39, as shown, are connected to a common shaft 42 which shaft is provided with a crank arm 43 for operating the same from another crank 44 through the medium of the link 45. The spring 46 tends to pull the crank 44 in position to close the damper 39. The crank 43 also has connected thereto a link 47 which is connected to one end of the arm 48 pivoted on the casing of the valve 41 by means of the upstanding member 49. This arm 48 has a free end 50 which is adapted to press downwardly on'the stem 51 of valve 41 when the dampers 39 are opened to also open valve 41 and provide the necessary steam jet for forcing a blast of air outwardly through the opening 38. The mechanism for operating the crank 44, will be has a shaft extending outwardly from it to I where the lever 55 is secured for turning the damperv to open or closed position. This lever 55 has at one end a depending weight 56 which tends to turn the damper towards closed position at all times. Secured. to the other endfo'f lever 55 is a cable 5'? which cable extends outwardly over a suitable guide pulley 58 and has at its lower ends s uitab e'handle 59 provided with a series ofi as shown in these uste notches such as at for engaging with the pin 61 on the lever 62 were it pro ects through the casing 63.

The degree of opening of the damper 53 may, of course, be varied by changing the setting of the pin 61 in the notches 60, and, if desired, suitable chain links such as 1nd1 cated at 64 may be inserted in the cable 57 for making further adjustments. These adjustments are necessary particularly in the installation of the system, because it Is always necessary to adjust the damper to the most eflicient ition for furnace operation, and by utilizing these ad ustments, the range of movement. of the furnace dam r may be varied to suit the conditions. he amount of angular movement of the dam 1' may also be varied by changing the position of the cable on the lever 55 sue for instance as securin it in the opening 65 instead of at the end of the lever.

The lever 62 is ivoted within the hous n 63 at 66. It also as ivoted thereto a ll 67 which link is slotted at its lower end at 68 to receive the pin 69 on the arm 70 of the device 70' which is a dashpot control devlce such as shown in F 6 and 7. This device,

gures, is merely a Houdaille hydraulic shock absorber which is adapted to permit the arm 70 to move fairly rapidly in one direction, and to oppose rapid motion thereof in the opposite direction. This is accomplished, as shown in Figs. 6 and 7, in which Fig. 7 is a section lookin at the absorber from the opposite side to t at in Figs. 2 and 3 by having the compartments indicatedat 71 and 72 filled with a suitable liquid communicating with the bore and the shaft 73 through the opening 74, and this bore in turn communicating with openings 75 and 76 into chambers 77 and 78.

Now, as the shaft 73 turns together with its lateral extensions 79 and 80 in a clockwise direction as-shown in Fig. 7, the liquid is laced under pressure between the members 9 and 80 and the partition 81 which is stationary. This pressure forces the li uid into the bore of the shaft past the nee e valve 82 and outwardly into the chambers 77 and 78 at a relatively slow rate which can be adjusted by means of the handle 83 on the needle valve. However, if the shaft is turned in the opposite direction, the check valves 81 in the partition 81 permit a relativel rapid passage of the fluid from the chambers 77 and 78 back into the chambers 71 and 72; and in this manner a retarded action in one direction for the arm 70 may be obtained. A f

sprin 84, the tension of which ma be adby means of the wing nut is aacured to the free end of the arm tend to draw it upwardly at all times.

Using the device shown in Figs. 6 and 7 for this particular structure, the arm 70 is made to oppose rapid motion in a counter- 70soasto b move rather rapidly The link 86 concrank 87 on shaft 13,

clockwise direction and in a clockwise direction.

nects this arm to the its lower end as at 88 so but is slotted at that, as the shaft 13 turns in a clockwise direction, the link 86 will only move upwardly as fast as the arm 70 is permitted to move under the influence of the spring 84 bIyI the construction shown in Figs. 6 and 7. ever, on the downward stroke of shaft 13, link 86 always brings the arm 70 to its lowermost position.

The period for which the arm 70 is set to move upwardly under the influence of the spring 84, is varied to suit the particular installment, and is preferably made suflicient- 1y long, so that in the normal operation the shaft 13 where it is continuously feeding coal through the pusher mechanlsm hereinbefore described, arm 70 never extends high enough to strike the free end of the crank 89.

However, when the shaft 13 is stopped with i the arm 87 in its uppermost position due'to the effect of the limiting switch 18, then arm 70 will move upwardly under the influence of the spring 84, strike the crank 89, and turn it so as to remove the latch 90 from the roller 91 on lever 62 and thus release lever 62 for movement upwardly. Arm 70 will, of course, by this time have passed far enough upwardly that its free end will be in the u per portion of the slot 68, and the weig t on the damper lever will, through the medium of the cable, pull the lever 62 u wardly into the position shown in Fig. 2. is upward p0sition of the lever 62, of course, is limited by the set screw 92 which forms another and finer adjustment for the regulation of the openin of the damper.

Anot er result of the upward movement of the lever 62 is to bring the end opposite the pin 61 downwardly so that it will exert a downward pull on the link 93 b means of the pin extending through the s ot in this link, and this action will turn the crank 94 downwardly to in turn force the crank arm 44 secured to the same shaft 94' downwardly and thus through the medium of the link 45, and lever arms 43 and 48 close the air inlet control damper 39 and the valve 41 controlhug the steam supply. A suitable dash pot arrangement is shown at 95 as connected to the free end 96 of lever 62 for prevent too sudden a swing of this lever under the influence of the weight 56.

From the above description, it will be seen that I have provided a very simple and efective means whereby all of the operating mechanism of the furnace is automatically started and stopped in proper timed relation y the opening and closing of the single switch 17 that may be controlled either from the temperature of the furnace or the steam pressure in the boilers. That is to sa when the motor is started by the closing 0 switch a drive shaft operatively connected 17, the fuel feeding mechanism is operated from shaft 13, and at the same time link 86 pulls down on the arm to in turn move lever 62 to open the damper 53 and turn on the fluid blast by opening dampers 39 and valve 41. Then when the switch 17 is opened either automatically or manually, the limit switch 18 will keep the motor running until shaft 13 is in proper position to level the gratesQ i and permit the upward movement of arm 70 under the influence of spring 84. After the motor stops by opening its own circuit through the actuation of the limit switch 18, arm '50 will gradually move up wardly to strike the crank arm 89 and release lever 62 so as to close the damper and shut off the fluid blast by closing the doors 39 and. valve 41.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a furnace having fuel feeding means, an outlet for the gaseous products of com.- bustion and a damper controlling said outlet, power means for operating said fuel fecding means, and control. mechanism interconnecting said power means and damper to automatically adjust said damper when the fuel feeding means is started or stopped, said control mechanism including means for closing said damper at a predetermined time after the fuel feeding is stopped.

2. Operating means for furnaces comprising fuel feeding mechanism, a Stoker grate, to said mechanism and said grate for driving the same, a damper controlling the outlet of gaseous products of combustion from said furnace, means for closing said damper, and control means associated with said shaft to permit operation of said damper closing means only after said shaft is stopped.

3. In a furnace having fuel feeding means, a motor operating said means to advance fuel into the furnace, a damper controlling the outlet of gaseous products of combustion from said furnace, and means controlled by said motor for moving said damper toward closed position only after said fuel feeding means has ceased to advance fuel into the furnace.

4. In a furnace, a stocker grate, means including a motor for operating said grate to advance fuel in said furnace, a damper controlling the outlet of gaseous products of combustion from said furnace, said damper being interconnected with said grate operating means so as to be controlled thereby, said operating means being operative to close said damper only after it has ceased to operate the grate.

5. In a furnace having fuel feeding means, motor operating said means to advance fuel into the furnace, a damper controlling the outlet of gaseous products of combustion from said furnace, and means controlled by said motor for operating said damper, said last named means including mechanism for closing said damper only after the motor is stopped.

6. Operating mechanism for furnaces including a main drive unit, fuel feeding mechanism driven by said unit, means for forcing fluid into the furnace controlled by said drive unit, said last named means including mechanism cutting off said fluid forcing means only after the motor is stopped.

7. In a furnace having fuel feeding means, a damper controlling the outlet of gaseous products of combustion from the furnace, means for forcing fluid into said furnace, con.- trol means including damper closing mechanism and cut off mechanism for said fluid forcing means interconnected with said fuel feeding means so as to cut off the fluid and move the damper toward closed position after stopping of the fuel feeding means.

In witness whereof, I hereunto subscribe my name this 11 day of April A. D., 1929.

GEORGE A. KOHOUT. 

